@foxnews: Coke or Pepsi? For some Americans, there is only one right answer. The decades-old cola rivalry is still going strong, but experts say the fierce loyalty may go deeper than subtle differences in sweetness, citrus and flavor. Research suggests branding and the memories people associate with these iconic drinks can shape how they perceive the taste itself. And despite the rivalry, Classic Coke remains America's top-selling soda, while Pepsi ranks third behind Dr Pepper.